Comparison of navigator-gated and breath-held image acquisition techniques for multi-echo quantitative dixon imaging of the liver in children and young adults

Leah A Gilligan; Jonathan R Dillman; Jean A Tkach; Andrew T Trout

doi:10.1007/s00261-019-01960-1

Comparison of navigator-gated and breath-held image acquisition techniques for multi-echo quantitative dixon imaging of the liver in children and young adults

Abdom Radiol (NY). 2019 Jun;44(6):2172-2181. doi: 10.1007/s00261-019-01960-1.

Authors

Leah A Gilligan¹, Jonathan R Dillman^{1

2}, Jean A Tkach¹, Andrew T Trout^{3

4}

Affiliations

¹ Department of Radiology, MLC 5031, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH, 45229, USA.
² Department of Radiology, University of Cincinnati College of Medicine, Cincinnati, OH, USA.
³ Department of Radiology, MLC 5031, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH, 45229, USA. [email protected].
⁴ Department of Radiology, University of Cincinnati College of Medicine, Cincinnati, OH, USA. [email protected].

PMID: 30815713
DOI: 10.1007/s00261-019-01960-1

Abstract

Purpose: Acquired over a breath hold, multi-echo Dixon (mDixon) magnetic resonance imaging (MRI) of the liver can be used to quantify proton density fat fraction (PDFF) and iron-related signal decay. However, young, obese, and co-morbid patients may have limited breath holding capacity and could benefit from a motion-robust mDixon acquisition. The purpose of this study was to compare hepatic PDFF and R2* values between navigator-gated and breath-held mDixon MRI acquisition techniques in children and young adults with suspected liver disease.

Materials and methods: This retrospective study was institutional review board-approved with a waiver of informed consent. Patients who underwent liver MRI with breath-held and navigator-gated mDixon sequences between January 2017 and July 2018 were included. One reviewer, blinded to sequence, measured PDFF and R2* on four images from each sequence. Another blinded reviewer graded respiratory motion (5-point Likert scale). Pearson correlation (r), Lin's concordance coefficients (r_c), and Bland-Altman analyses were used to assess agreement between techniques. Frequency of clinically limiting motion (score ≥ 3) was compared with Fisher's exact test.

Results: Forty-two patients were included (15 female, 27 male; mean age: 15.7 ± 4.6 years). Mean PDFF and R2* were 16.6 ± 13.1% and 29.3 ± 4.7 s^-1 (breath-held) versus 17.0 ± 13.2% and 29.6 ± 5.2 s^-1 (navigator-gated). PDFF agreed almost perfectly between sequences (r_c = 0.997, 95% CI 0.994-0.998; mean bias: 0.3%; 95% limits of agreement: - 2.4 to +1.7%), while R2* values correlated very strongly but with poor agreement (r = 0.837, r_c = 0.832, 95% CI 0.716-0.910). Navigator-gated images exhibited significantly higher frequency of clinically limiting respiratory motion (88% vs. 48%, p = 0.0001).

Conclusion: Despite greater respiratory motion artifact, a free-breathing navigator-gated mDixon sequence produces PDFF values with almost perfect agreement to a breath-held sequence.

Keywords: Liver MRI; Pediatric; Proton density fat fraction; R2*; Respiratory triggering; T2*.

Publication types

Comparative Study
Research Support, Non-U.S. Gov't

MeSH terms

Adolescent
Artifacts
Breath Holding
Female
Humans
Image Interpretation, Computer-Assisted / methods
Liver Diseases / diagnostic imaging*
Magnetic Resonance Imaging / methods*
Male
Retrospective Studies
Young Adult